Vertical farms are the brainchild of Columbia University professor Dickson Despommier, who stumbled onto the idea almost by accident in 1999.

As a class project, Despommier challenged his medical ecology students to feed 50,000 people using thirteen acres of rooftop gardens. The students were unsuccessful, but when Despommier suggested they instead try growing plants vertically on every floor, the project changed course.

The idea has since drawn the interest of investors and architects from across the globe. The "Living Tower" design seen here is complete with solar panels, a rainwater purification system, and two large wind turbines on top for energy production.